Persistent patellofemoral symptoms can cause patient dissatisfaction after Total Knee Arthroplasty (TKA). The aim of this retrospective study was to evaluate patellar tracking and patient outcomes utilizing two implant designs in TKA.

Medical records and radiographs of two groups of 100 consecutive patients each were reviewed. All patients underwent posterior stabilized TKA by a single surgeon; using the same operative technique but two different implant designs (Group 1: Asymmetric femoral component with deep congruent trochlear groove and Group 2: Asymmetric femoral component with shallow trochlear groove). Data was collected on demographic characteristics, patellar tilt, displacement, prosthesis-bone angle, HSS Patella Score, Knee Society Knee and Function Score. Patellar tilt more than 5° was considered significant. Statistical analysis was done using the SPSS v.16.0.3 software (SPSS, Inc., Chicago, IL).

Patients' age and sex were equivalent in the two groups (p>0.57). Median follow up was 2.2 years. Pre-operative incidence of patellar tilt was similar in both groups (18% vs. 17%). After surgery, these values changed to 30% and 77% respectively. This was statistically significant (p<0.001). The Knee Society Knee and Function Score improved significantly in both groups, however the improvement in the function score was significantly greater in the first group (p=0.001). The improvement in Knee Society Knee Score (50.24 and 48.08; p= 0.18) and post-operative HSS Score (93 vs. 91; p=0.19) were not statistically significant.

Our findings suggest that despite using the same operative technique, patellar tracking was significantly different between the two groups, a finding most likely attributable to the design of the femoral component. Whether the difference in patellar maltracking will affect long-term survival of the patellar component remains to be seen.

Introduction

Although Total Knee Arthroplasty (TKA) has been shown to correct abnormal frontal plane knee biomechanics, little is known about this effect beyond 6 months. The purpose of this study was to compare sequentially the knee adduction moment during level-walking before and after TKA in varus knees. We hypothesized that adduction moment would diminish after TKA proportionate to the tibio-femoral realignment in degrees.

Introduction

Studies have documented encouraging results with the use of fluted, tapered, modular, titanium stems in revision hip arthroplasty with bone loss. However, radiographic signs of osseointegration and patterns of reconstitution have not been previously categorized.

Introduction

It is not uncommon to encounter patients with atypical hip or lower extremity pain, ill-defined clinico-radiological features and concomitant hip and lumbar spine arthritis. It has been hypothesized that an anaesthetic hip arthrogram can help identify the source of pain in these cases. The purpose of this study is to analyze our experience with this technique in order to verify its accuracy.

Implant related hypersensitivity is an infrequent complication after total knee replacement. It remains a relatively unpredictable and poorly understood cause of failure of an implant.

We present a report of five patients who presented with persistent hypertrophic synovitis after total knee replacement using a cobalt chrome component. Extensive preoperative and intraoperative attempts ruled out infection as a cause of symptoms. The knees had good ligamentous balance and were well aligned and fixed.

The clinical condition improved after revision to a zirconium femoral and titanium metal backed tibial components. Intraoperative histopathology revealed thickened synovium with a predominantly monocellular (lymphocytic or histiocytic) response.

Where infection has been excluded as a cause of persistent pain and swelling, consideration should be given to metal allergy as a cause of failure in primary knee replacement surgery.

Failure of internal fixation of intertrochanteric fractures is associated with delayed union or malunion resulting in persistent pain and diminished function. We evaluated 15 elderly patients treated with a tapered, fluted, modular, distally fixing cementless stem.

At an average follow up of 2.86 years, mean Harris hip score improved from 35.90 preoperatively to 83.01 (P < 0.01). Fourteen stems had stable bony ingrowth and one stem was loose. Distal fixation with a tapered fluted modular cementless stem allows stable fixation with good functional outcome in a reproducible fashion in this challenging cohort of patients.

Introduction: Failure of internal fixation of intertrochanteric fractures may be associated with delayed union or malunion resulting in persistent pain and diminished function. The purpose of this study is to evaluate results of the use of a tapered, fluted, modular, distally fixing cementless stem in the management of failed treatment of intertrochanteric hip fractures in elderly patients.

Methods: 837 patients had internal fixation of intertrochanteric fractures over a seven year period (2000–2007) at our institution. Of these, 15 patients with mean age of 80.6 years (69.8–92.3), underwent hip arthroplasty for failure of internal fixation. Clinical and radiographic records of these patients were evaluated.

Results: At an average follow up of 2.86 (2–4.5) years, all patients showed marked functional improvement with change in mean Harris hip score from 35.90 to 83.01 (P < 0.01). Fourteen stems had stable bony ingrowth and one stem was loose and subsided by 5 mm. Three patients used a walker for ambulation, ten patients used a cane and two could ambulate without aids.

Conclusion: Use of a tapered fluted modular cementless stem allows stable distal fixation in a reproducible fashion with good functional outcome in this challenging cohort of patients. All patients were ambulatory, however majority used walking aids.

Introduction: Studies have shown a strong relationship between knee osteoarthritis (OA) and the adduction moment at the knee during gait. Total knee arthroplasty (TKA) is known to improve range of motion and function in patients with severe OA. Examinations of tibial bearing wear suggest that although the static alignment of the joint is restored, the abnormal dynamic loading conditions may still remain. The aim of this study was to compare the pre-op and post-op knee biomechanics during gait in patients undergoing TKA.

Methods: Gait analysis was performed on 15 patients with 17 TKA’s (8 women and 7 men, all with pre-op varus knee alignment) prior to, 6 months and 1 year following TKA. Reflective markers were placed on the lower extremity of each patient and motion data were collected at 60 Hz using six infrared cameras (Qtrac, Qualysis). Ground reaction forces were recorded at 960 Hz with a multicomponent force plate (Kistler). The frontal plane knee moment (adduction/abduction) was calculated for each trial using inverse dynamics. Based on the anterior/posterior ground reaction force, the stance phase of each trial was divided into a braking phase and a propulsive phase. The area under the knee adduction moment curve (knee adduction impulse) was calculated for each phase. A repeated-measures (Time x Phase) ANOVA was used to compare changes in the peak knee adduction moment and knee adduction impulse for each phase over time. P-values less than 0.05 were considered significant.

Results: Mean knee alignment was 4.75 degrees varus pre-op and 4.25 degrees valgus post-op (P < 0.001). A significant time-by-phase interaction was found for peak adduction moment (P = 0.002) and a nearly significant time-by-phase interaction was found for adduction impulse (P = 0.056). In braking phase, six months after surgery, knee adduction impulse and peak moment decreased 26% and 15% respectively. At one year, however, both increased by 20% and 19% respectively to near pre-op levels. In propulsive phase, knee adduction impulse and moment decreased 34% and 25% respectively at 6 months but only increased by 4% and 11% respectively at one year follow-up. Knee Society and Function scores improved from 50.17 and 61.67 pre-op to 82.08 and 82.50 at 6 months and 88.83 and 85.83 at 1 year post-op (P < 0.001, respectively).

Discussion: After TKA, in the breaking phase of gait, the initial improvement in knee adduction impulse and peak knee adduction moment noted at 6 months disappeared completely indicating no improvement in medial compartment loading conditions at 1 year post operatively. The improvement in these parameters during the propulsive phase remained persistent at 1 year although there was some tendency to revert back to pre-operative levels. This would suggest that restoration of anatomic axial alignment and soft tissue balance do not change the medial loading conditions following TKA.

One of the most important factors on which Total Knee Replacements results depend is accuracy of restoration of normal mechanical axis. It is believed that computer navigated TKR give better implants position therefore should improve long term results. We decided to check if computer navigation actually improves restoration of mechanical axis and implants placement in a single surgeon, single implant type series. We prospectively assessed 58 patients (60 knees). Each group (navigated versus non navigated) consisted of 30 knees. Patients were assessed clinically and radiographically using weight bearing full-length AP and short lateral films (PACS and IMPAX software). Clinical Results at 2 years were comparable in both groups (89% vs. 88% good or excellent result). Radiological results proved to be better in navigated knees regarding mechanical axis. There were no statistically important differences in other radiological parameters.